Window Insulation Tips to Save on Heating Costs in Winter

A Large Amount of Home Heat Escapes Through Windows

In homes with poor insulation, a significant amount of indoor heat escapes through windows and their gaps. This is because, even for the same area, glass windows have much lower insulating performance than walls. That is why properly sealing only the windows can noticeably reduce the heating needed to maintain the same indoor temperature.

Start by Stopping Drafts Through Gaps

Before applying insulation materials, it is most effective to first block the gaps where cold air enters between the window frame and the window. Turn off the lights and hold a candle or tissue near the gaps; wherever it moves, you can easily identify where air is leaking in. Apply weatherstripping, such as pile tape, to those areas.

1. Wipe dust and moisture from the window frame and glass with a dry cloth to clean the adhesive surface.
2. Measure the length of the gap with a tape measure and cut the weatherstripping to match that length.
3. Apply the weatherstripping where it will be pressed when the window is closed, without interfering with opening and closing.
4. On the window glass, spray plenty of water with a spray bottle, then attach bubble wrap with the raised side facing the glass.
5. Finish the edges of the bubble wrap with clear tape so it stays firmly in place and does not lift.

Reinforcements That Improve Insulation

• Hang thick blackout curtains long enough to just touch the floor to reduce heat loss overnight.
• During the day, open the curtains to let in sunlight, then close them as soon as the sun sets to trap the warmed air.
• For gaps under the front door, use floor weatherstripping or a long fabric draft stopper to block cold air.
• For windows that are rarely used, apply high-insulation window film or thick bubble wrap in two layers.

Do Not Overlook Condensation and Ventilation

If windows are sealed too tightly, warm indoor air can meet the cold glass and easily form condensation. If condensation is left alone, mold can grow on the window frame, so open the windows wide 2 to 3 times a day for 5 minutes and ventilate with cross-breezes. When using gas or kerosene heaters, there is a risk of oxygen deficiency and carbon monoxide, so do not leave them running for long periods in enclosed spaces, and ventilate regularly whenever possible.